Hmmm - - thinking of building something like this and thought you guys might offer some insight as your well ahead of the curve electrically/software wise.

http://rcarduino.blogspot.com/2012/0...-part-one.html

I was wondering why does the IR have to blink to a frequency for a system like this to work? If your just trying to detect one car why cant you just power up a LED from your receiver (resister inline of course as needed). I only have typically one car on a local backyard track at a time and was hoping to setup something like this for hot-laps - but want a simpler transponder.